Mainframe computers are powerful, multi-processor computing devices that have high throughput and are able to perform thousands of computing tasks every second. Processing capacity of the mainframe computers is often measured in terms of millions of service units per hour (MSUs) that are used to execute the computing tasks
A logical partition, commonly called an LPAR, is a subset of a computer's hardware resources (e.g., processors, memory, and storage), virtualized as a separate computer. In effect, a physical mainframe computer can be partitioned into multiple logical partitions, each hosting a separate operating system instance. A mainframe computer may support one or more LPARs for computing work. Many applications may be run or executed concurrently on an LPAR.
Enterprises and organizations often rely on mainframe computers for their computing needs, for example, for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and transaction processing. Instead of maintaining their own mainframe computer installations, the enterprises and organizations (hereinafter “mainframe customers”) may get a license to use processing capacity on a mainframe computer installations maintained by an external provider or vendor.
Under common license arrangements (e.g. IBM's Monthly License Charge (MLC)), a mainframe customer may obtain a license to use a limited amount of processing capacity on one or more logical partitions (LPARs) of the mainframe computers to run the customer's applications or software. The licensed processing capacity, which may be measured in terms MSUs, may be a function of the individual LPAR, time of use, etc. The licensed processing capacity may, for example, be a “Defined Capacity” (DC) for an individual LPAR or a “Group Capacity” (GCL) for a group of LPARs. The licensed processing capacity may include a maximum or total capacity limit for the computer system across all LPARs.
The customer may run several applications (“computing workload”) on each LPAR concurrently. The customer may use a capping product or solution (e.g., a third party capping product or solution) to manage distribution and execution of the customer's computing workload on the mainframe computers within the processing capacity limits. The processing capacity limits are usually enforced by the capping product or solution on a rolling average basis allowing instantaneous workload demand to exceed the processing capacity limits.
Consideration is now being given to managing capping limits on CPU usage of one or more LPARs, while optimizing capacity usage across the LPARs by aligning workload allocations based on utilization needs, workload importance, and customer policy profiles.